Some simple answers to common related questions....
Q: Why haven't I heard of Cherry Amplifiers or Digital Amplifier Company before?
A: In a word, ADVERTISING. We do almost none of it. Why? More value for our customers. Same goes with trade shows. Here's a little something about the company, and about ME:
http://positive-feedback.com/interviews/tommy-obrien-digital-amplifier-co/Q: Why are Cherry Amplifiers different?
A: We design for sonics. Our impressive bench measurements may be a few dB less here and there than the "competition", but very much world class. Number one is the sound for us.
Q: Are Class-AB or Class-A amps better than Class-D?
A: In some cases, yes, but Class-D can achieve higher levels of sonic performance when done right, aside from some extreme cases in analog amps (the $100k, 300 lb variety?). However, within reasonable cost constraints, well designed Class-D can outperform conventional amplifiers in every respect that matters for listening. The problem is that almost all Class-D suffers from a serious design flaw.
Q: What is this serious Class-D design flaw you speak of?
A: Simply put, control. Technically, feedback control/topology. The sad truth is that almost every Class-D designer uses gobs and GOBS of negative feedback and/or complex phase shifting networks to get decent, and sometimes deceivingly amazing bench measurements. Most audiophiles know the difference between sonic performance and bench measurements, but the misconception of better measurements tending to mean better sound is no coincidence. Old fashioned amplifiers were much easier to tell apart that way.
Q: Why do you (Cherry Amplifier®) claim better sound than other Class-D amps?
A: Our designs, which are home-grown, are first put together with ideal component values to get noise and distortion well below audible levels, then we tweak the circuits for sonic improvement. This usually costs us a little bit in the specifications, but is a tremendous advantage sonically. The other reason is that we DO NOT use gobs of feedback. We DO NOT use complex phase compensation networks. Instead, we make our output circuits well controlled and we make our output filters inaudible. This way, we don't need to put a massive feedback loop around the amplifier, which is the way just about everybody else is doing it, even today after the lessons the 1980s taught us. Fact is, most Class-D designers weren't designers back in the 1980s. Not to age myself, but I was, and I remember the strident and screechy sound of the old Adcom Class-AB amps with their obscene amounts of corrective feedback. Remember that feedback can't correct for errors that already happened, so it changes the future signal such that the average over time adds up to approximately the desired signal. Did you catch that? The error happens, then the counter error happens, and all this is going into your speaker, then into your ears!
If you enjoyed this post, feel free to ask for more of the same. Believe me, I could go on and on and on....
-Tommy O
